Out of the following,which type of interaction is responsible for the stabilisation of $\alpha$-helix structure of proteins?

The acid showing salt-like character in aqueous solution is

Assertion $(A)$: An optically active amino acid can exist in three forms depending on the $pH$ of the solution.
Reason $(R)$: Amino acids contain both acidic and basic groups; they exist as a zwitterion in aqueous medium,anionic form in basic medium,and cationic form in acidic medium.

Denaturation of proteins leads to loss of its biological activity by

Which of the following molecules has the ability to form a zwitterion?

Which is not true for arginine?